Self-cooling canned pump and refrigeration system containing the same



Feb. 28, 1967 c. A. WILSON 3,3

SELF-COOLING CANNED PUMP AND REFRIGERATION SYSTEM CONTAINING THE SAMEFiled March 1, 1965 2 Sheets-Sheet 1 Feb. 28, 1967 c. A. WILSON3,306,074

SELF-COOLING CANNED PUMP REFRIGERATION SYSTEM CONTAINING E SAME FiledMarch 1, 1965 2 Sheets-Sheet 2 I28 127 B I25 F 1x KVQ I 2 19 II N l3 /4I5 Q G) A U 1 PUMP RESERVOIR 3 REFRIGERATING PROCESS COOLER 3 V W 1 l9 5j I I I32 J I38 14 PUMP United States Patent 3,306,074 SELF-COOLINGQANNED PUMP AND REFRIGER- ATION SYSTEM CONTAINING THE SAME Charles A.Wilson, Lincoln, Rl, assignor to Pall Corporation, Glen Cove, N.Y., acorporation of New York Filed Mar. 1, 1.965, Ser. No. 435,794 9 Claims.(Cl. 62-5tl5) This invention relates to a canned or close-coupled pumpprovided with a heat exchanger as the pumping means for a refrigerationsystem especially designed for use in which the refrigerant fluid is thecooling fluid for the pump heat exchanger. More particularly, it relatesto a canned pump having a motor chamber in closecoupled relationship tothe impeller chamber and cooling means for indirectly cooling thecooling and lubricating fluid within the rotor chamber with arefrigerant itself pumped by the pump in a refrigeration system and torefrigerant systems including such pumps in combination therewith.

In most canned pumps, the motor parts, e.g., the shaft bearings for therotor drive shaft, are lubricated by the fluid being pumped. Whenutilizing a canned pump for the pumping of a compressed vapor-type ofrefrigerant, however, it is generally necessary to have a. separatefluid system for lubricating the motor parts, since the refrigeratingliquid is usually pumped at its vapor pressure, and accordingly wouldvaporize immediately upon being subjected to any additional heat if itwere allowed to flow through the motor. This of course renders itunsuitable as a lubricating fluid for the motor parts. Hence, in such acanned pump, the motor chamber is separated from the impeller chamber sothat pumped fluid cannot circulate through the motor chamber. Thus, themotor chamber fluid is cooled either by heat transfer through the motorchamber walls to the outside air, or by a separate heat exchanger, oneside of which is in fluid-flow connection with the motor chamber.Through the second side of the heat exchanger is passed a separatecoolant fluid in heat exchange relationship with the motor chamberfluid.

This use of a separate external coolant will, of course, 7

require a separate circulating system and a separate pump, and thus twoadditional liquids are required for lubrication and cooling.

There have been canned pumps, such as shown in US.

Patent No. 2,986,905 to Kooher et al., dated June 6, 1961, a 1

which have a refrigerant system wherein the pumped compressed vapor-typerefrigerant, such as Freon, is passed through the interior of the motorchamber to directly cool the motor. This necessitates the use of sealedlubricated bearings for the motor shaft, as the evaporating refrigerantof course provides no lubrication. in the lubricated tem and Kocher 1,for removing fluid.

The use of external cooling coils for cooling the motor chamber liquidwith a separate coolant is well-known to the prior art, and isexemplified by U.S. Patents Nos. 2,687,695 to Blom et al., dated August31, 1954, and 3,013,500 to Bollibon et al., dated December 19, 1961. Inboth of these cases a cooling coil is in fluid flow relationship withthe interior of the motor chamber such that motor fluid passes out fromthe motor chamber through the coil and back to the motor chamber. Thecoil is disposed in a cooling chamber through which is passed thecoolant liquid.

The canned pump of this invention comprises a housing defining animpeller chamber and a motor chamber, an impeller in the impellerchamber, an inlet and an outlet in the impeller chamber for circulationof fluid to be The oil bearings often leaks into the pump sysdiscloses aseparator unit, 25 in FIGURE the lubricating oil from the refrigerantpumped therethrough and an inlet and an outlet in the motor chamber, forcirculation of lubricating and cooling fluid therethr-ough, a heatexchanger having a heat exchanging surface separating the heat exchangerinto two sides, fluid connections connecting one side thereof with themotor chamber and a fluid connection connecting the other side with theimpeller chamber for heat exchange between fluid circulating in themotor chamber with fluid passing through the impeller chamber. It shouldbe understood that the term pump includes a compressor, as well.

This pump makes it possible to utilize the pumped fluid, to cool thelubricating and cooling fluid in the motor chamber, and also to pump acompressed vapor-type refrigerating liquid and use this pumped fluid asthe cooling and lubricating fluid for the motor chamber, without theneed for sealed lubricated bearings.

When pumping the vapor-type refrigerant at its vapor pressure, it isnecessary to prevent the fluid in the motor chamber from vaporizing as aresult of the heat generated by the motor. This is accomplished in thepump of the invention by providing pressure connections between themotor chamber and a high pressure portion of the irnpeller chamber topressurize the motor chamber fluid above its vapor pressure, whilepreventing it from becoming too Warm by cooling it in the heatexchanger, where it is passed in heat exchange relationship with aportion of the fluid being pumped. The refrigerant fluid leaving theheat exchanger after cooling the motor chamber liquid is returned to therefrigerating system.

The pumps of the invention introduce canned pumps for the first time torefrigerant systems, which could not utilize canned pumps, withoutconsiderable modifications. The canned pump of the invention possessesthe usual attributes of such pumps: compactness, and a generallyleakproof design, which is obtainable at a minimum of expense andtrouble. Leakproofness is accomplished by eliminating the need for amoving seal, e.g., at the bearings or at the juncture between therotating drive shaft and the casing of the pump. Heretofore, because ofthe low boiling point of refrigerant fluids, it has been necessary touse sealed lubricated bearings, or a separate lubricating and coolingfluid for the motor compartment, which would require special seals toprevent contamination of the refrigerant fluid by the lubricating fluid,thus increasing substantially the initial expense as well as the cost ofupkeep. Kocher et al., for example use a special separator tank forremoving entrained oil from the pumped refrigerant liquid. This is anadded expense which would not be necessary with a pump of the new typeherein described. This invention now makes it possible to pump amaterial at its boiling point and utilize the same fluid as the motorlubricating and cooling fluid thereby doing away with the additionalexpense and trouble inherent in using a different lubricating fluid.

However, in the circumstances where the liquid refrigerant is itselfincapable of acting as a suitable lubricating and cooling fluid, aswhere it is corrosive or abrasive, it is possible to utilize a separatefluid in the motor chamber cooled by the pump fluid in the heatexchanger. This would usually require, however, a seal between the motorand impeller chambers of the pump to prevent leakage.

The refrigerant system of this invention comprises, in combination, arefrigerant reservoir, which preferably contains a refrigerant in theliquid phase at its boilng point and in the vapor phase in contact withthe liquid phase, a pump having a housing defining an impeller chamberand a motor chamber, an impeller in the impeller chamber, an inlet andan outlet in the impeller chamber for circulation of fluid to be pumpedtherethrough and an inlet and an outlet in the motor chamber forcirculation of lubricating and cooling fluid therethrough, a heatexchanger having a heat exchanging surface separating the heat exchangerinto two sides, fluid connections connecting one side thereof 'with themotor chamber and fluid connections connecting the other side with theimpeller chamber and the reservoir for heat exchange between fluidcirculating in the motor chamber with fluid passing through the impellerchamber and conduit means for flow of refrigerant liquid between thereservoir and the impeller chamber.

It is preferred to utilize the pumped fluid as the cooling andlubricating fluid within the motor chamber, to eliminate the need forexpensive and troublesome fluidtight seals between the impeller andmotor chamber. When the fluid in reservoir is at its boiling point,however, as in the case of a refrigerant liquid of the compressed vaportype,'it is necessary to pressurize the fluid in the motor chamber toprevent it from boiling immediately upon absorbing the motor heat. Thisis accomplished by providing a pressure connection between a highpressure portion of the impeller chamber and the motor chamber, whichtransmits pressure from the impeller chamber. It is preferable that thisconnection have means to prevent the flow of fluid from the motorchamber into the impeller chamber, and vice versa.

Preferably, the pumped refrigerant is tapped for heat exchange purposesat the exhaust from the impeller chamber. This eliminates the necessityfor having a separate pump solely for circulating the refrigerant. Wherethe refrigerant is of the compressed vapor type, to obtain the mosteffective cooling, the liquid will be bled into the second side of theheat exchanger so as to flash upon coming into contact with therelatively hot heat exchange surface separating the two sides of theheat exchanger. To insure the flashing of the refrigerant immediatelyupon entering the heat exchanger a flow restrictor can be inserted inthe inlet to the second side of the heat exchanger such that the pumprefrigerant passing ino the heat exchanger from the outlet of the pumpwill immediately experience a pressure drop and will flash. Analternative method would be to allow the refrigerant to pass into theheat exchnger and then to allow the refrigerant liquid to boil thereinas it passes through. The refrigerant vapors passing out from the heatexchanger are returned to the main refrigerating system.

The position of the heat exchanger vis-a-vis the pump, as well as thetype of heat exchanger chosen, are not critical to the invention. Theirposition and the type will be determined by the amount of heat exchangesurface necessary for providing sufficient cooling capacity for themotor fluid, space requirements for the particular pump, and any otherfactors peculiar to a given situation. For example, the heat exchangercan be of the shell-andtube type wherein the motor chamber fluid willpass through the tube side of the heat exchanger, or the heat exchangercan be of the coiled tube type wherein the motor chamber fluid will passthrough the coil of the heat exchanger. When using a vapor-type ofrefrigerant, it is preferred to pass the pumped liquid into a largehousing, such as the shell side of a tube-and-shell, or coiled tube,heat exchanger.

The heat exchanger may be located at a distance from the canned pump orit can be attached to the pump housing. It can be attached to the motorchamber end of the pump, as is shown in the drawing, or it can belocated in an annular jacket around the pump. Various embodiments areknown in the prior art, and a preferred embodiment is described in thedrawings.

FIGURE '1 is a sectional view of an embodiment of a canned pump of thisinvention,

FIGURE 2 is a flow sheet of .a refrigeration system utilizing the cannedpump of FIGURE 1, and

FIGURE 3 is a flo'w sheet of a second type of refrigeration systemwherein a canned pump of the type shown 4 in FIGURE 1 acts as thecompressor for the refrigeration system.

The pump of FIGURE 1 comprises a housing 11 which is formed in threesections, the heat exchanger section 13, the motor section 14, :and theimpeller section 15. The sections are bolted together by bolts 17. Themotor section is formed in two parts 14a and 14b which are also boltedtogether for ease of maintenance. The motor section has an open end,which is closed off by end plate 56, also bolted on.

The impeller section 15 includes an impeller chamber 22 having an outlet19, an inlet 20 and an impeller 21 rotatably supported therein, in fluidflow impelling relationship between the inlet and outlet. The impellerhas an internal volute 26. The pump section 15 also has a volute 7formed in the impeller chamber 22, complementing the impeller volute 26.Although the impeller in this embodiment is of the centrifugal type, theinvention is equally applicable to any other type of motor pump, such asa turbine pump or a gear pump.

The motor section contains a motor rotor chamber 31, which is separatedfrom the impeller chamber 22 by the end plate 36. Plate 36 at itsexternal periphery, is held by the ledge 32 on the pump section housing15 against the thrust plate gasket 34, and the entire assembly of plate36 and gasket 34 are held in a fluid-tight seal between housing sections14 and 15 by bolts 17. Pressure ports 5 and 6 extend through plate 36and connect the impeller chamber 22 to the motor rotor chamber 31 at aposition close to the outer circumference of the motor rotor chamber 31,to tap the high pressure at this portion of the impeller chamber.

A support bearing 46 is press-fitted into a central passage 37 in endplate 36. The front end of rot-or shaft 28 passes through and isrotatably supported by the bearing 46. A bearing retainer 50 isconnected to the end of stator cup 40 abutting the end plate 36 andholds therein bearing 51 which supports the back end of shaft 28. Abarrier seal, in this embodiment, a lip seal 47, is located between theshaft 28 and an indentation in the passage 37 of the end plate 36sealing oiT flow of fluid in the motor rotor chamber along the shaftinto the impeller chamber 22. Bearing lubrication space 44 is defined inpassage 37 between the front end of bearing 46 and lip seal 47.

The impeller 21 is attached to drive shaft 28 by bolt 25, which isthreaded into the end of shaft 28. A neckeddown portion of the shaft 28extends through an opening 29 in the back side of the impeller 21. Therotor 42 is fixed to the shaft 28, to rotate therewith.

The shaft 28 has a central channel 35 running from the rear of the shaftto a position adjacent the front end of the shaft, beyond the bearing46. Radial channel 27 in the shaft 28 connects the central channel 35 tothe bearing lubrication space 44. A secondary impeller in the form oftwo radial arms 43 is attached to the shaft 28. The arms have centralchannels 48 connecting the central channel 35 of the shaft with themotor rotor chamber 31. The back end of the central channel 35 opensinto bearing lubrication space 52 formed within bearing holder 50.

The lubrication spaces 44 and 52 communicate directly with the motorrotor chamber 31 through the dogleg longitudinal and radial channels 45and 41, respectively.

Stator chamber 38 is annularly disposed just inside of the motor sectionhousing 14, defined by stator cup 40, and contains the stator 39. Thestator 39- is connected to a source of electrical power (not shown) viaelectrical wires 60. In this embodiment, the stator chamber is sealedoff from the rotor chamber 31. However, under certain conditions thismay not be desirable, and the rotor and stator chambers may be in fluidflow connection.

Cooling coil 53 is contained within the heat exchanger chamber 63. Oneend of the coil is in fluid connection with lubrication space 52 and isheld in place by the gland nut 54. The other end of the coil is in fluidconnection with the motor rotor chamber 31 through coil inlet 58 and isheld in place by the gland nut 55. The gland nuts 54 and 55 arethreadedly connected to raised bosses 3 on the end plate 56. The glandnuts 54 and 55 hold sealing glands 57 in place around the cooling coilends to prevent leakage between the motor rotor chamber 31 and heatexchanger chamber 63.

A vent valve 70 is attached to the cooling coil 53 through T 72 to allowventing of the coil through nipple 73 to the heat exchanger chamber 63.The slot-headed control leg 75 for the vent valve 70 extends throughaperture 76 in the housing section 13. Gland nut 77 and sealing gland 78prevent leakage from the heat exchanger chamber 63. The manuallyoperated vent valve described above can be readily replaced with any ofthe conventional automatic vent valves now commonly used.

Conduit 127 is thread-fitted into the pump section 15 at the outlet 19at one end and into the heat exchanger section 13 at its other endthrough the inlet 61. A plate 62 having an orifice 64 is placed in theinlet 61 and held between the end of conduit 127 and shoulder 133 in thehousing 13. Valve 130 is attached into conduit 127, and is normallyopen. The chamber 63 has an outlet 65 in which is similarly fitted aconduit 129 leading to the main refrigeration system.

In this type of canned pump, the motor operates in a fluid bath, i.e.,the motor rotor chamber 31 and cooling coil 53 are filled with a coolingand lubricating fluid. The bearings 46 and 51 are thus lubricated andcooled by the fluid, and the rotor 42 and shaft 28 are also cooled bythe same fluid. Similarly, by having the fluid flowing through the motorrotor chamber, the stator compartment 38 is also cooled.

The motor rotor chamber 31 is filled with pumped fluid through ports and6 from the impeller chamber 22. The fluid is allowed to fill the coolingcoil 53, shaft channel 35 and the motor rotor chamber itself before thepump is turned on. The vent valve 70 is open to permit venting while themotor rotor chamber and coil are being filled. When these spaces arefilled the vent valve 70 is closed by turning the slot-headed controlleg 75.

After these spaces are full, the pump is turned on, and

'as the impeller 21 rotates, the secondary impeller 43 also rotates,forcing circulation of fluid up through the central shaft, out throughthe secondary impeller arms 43, around the motor rotor chamber 31, downthrough inlet 58, into the cooling coil 53 an finally back to the motorrotor chamber 31 through space 52, whence it is recirculated via thecentral shaft impeller 43. A portion of the fluid is also passed throughbearings 46 and 51 for lubricating and cooling. The liquid in the motorrotor chamber 31 is pressurized above the pressure in the pump inlet byputting the ports 5 and-6 at the outermost portion of the motor rotorchamber 31, as far from the center of the impeller 21 as possible and bypreventing fluid flow along the shaft 28 with the lip seal 47.

The pumped compressed vapor refrigerant fluid enters the impellerchamber through inlet 20, passes through the eye of the impeller, isspun out through the volute 26 of the impeller 21, into the volute 22 inthe impeller housing section 15 and then out through the outlet 19 atthe required pressure. A portion of the pumped refrigerant is divertedthrough conduit 127 to the heat exchanger housing section 13. Therefrigerant passes through the orifice 64 and flashes upon entering therelatively hot and lower pressure heat exchanger chamber 63. Thelubricating liquid in coil 53 is cooled thereby, and the refrigerantvapor exits through outlet 65, and conduit I129, returning thence to themain refrigeration system.

The orifice plate 62 can be omitted, and the refrigerant fluid can beallowed to pass as a liquid into the heat exchanger chamber 63, withinwhich it will boil off, and exit through outlet 65. It is preferablethat the inlet be located at or near the lower portion of the chamber63, i.e., when the pump is horizontal, as shown in FIGURE 1, the inlet61 is at the bottom and the outlet 65 is at the top of the heatexchanger housing section 13.

In the embodiment shown in FIGURE 1, the refrigerant is passed throughthe shell side of a coil-and-shell heat exchanger. Although it would bepossible to pass the rotor fluid through the shell side and therefrigerant through the cooling coil, when utilizing a vaporizingrefrigerant it is considered preferable to allow the refrigerant tovaporize in the open shell space, and cool a liquid carried in a coil orin tubes passing therethrough. However, when the refrigerant used is ofthe non-evaporating type, the lubricating fluid and the refrigerantliquids can be passed through either side of the heat exchanger.However, even in that situation it is advantageous to pass the motorchamber liquid through the tubes or coil rather than through the shellspace, as it improves the circulation of the motor chamber liquid. Itwill be appreciated that the pumping power of the secondary impeller inthe rotor chamber is generally rela tively small, compared to the powerof the primary pump impeller and it requires less power to obtain asuitable circulation through a tube than through a relatively largechamber.

The various portions of the housing 11 are shown in FIGURE 1 as beingbolted together for ease of maintenance and breaking down the entireunit. However, it is also possible to weld the sections together, or tocast the housing into two axial halves, as opposed to the verticalsections shown herein, and either weld or bolt the sections together.

The material of construction will depend upon the fluid pumped and thetemperature at which it is operated. For highly corrosive materials, thepreferred material would be stainless steel. When using a differentmotor chamber fluid, the motor chamber can be sealed oil? completelyfrom the impeller chamber by closing ports 5 and 6 and the material ofconstruction of the motor housing section may be diiferent.

In the refrigeration system of FIGURE 2 the pump, generally designatedas 11, is divided into three sections, the impeller section 15, themotor section 14 and the heat exchange section 13 as shown in FIGURE 1.Reservoir 118 which includes an upper portion 119 for vapor phase abovethe liquid refrigerant in the lower portion 120 is connected at itslower portion 120 through conduit 122 to the inlet 20 of the impellersection 15. Conduit 125 leads from the outlet 19 from the impellersection, and includes gate valve 128. Conduit 127 connects to theinterior of the heat exchange section 13, and includes valve 130.Conduit 129 connects the section 13 to the vapor space 119 in reservoir118. The refrigerant liquid pumped through conduit 125 goes through arefrigerating system (not shown), Where it vaporizes Whilerefrigerating, and the vapors are eventually recompressed and returnedto the reservoir 118 in the liquid phase.

Alternatively, when the canned pump acts as the compressor for therefrigerating system, as shown in FIGURE 3, refrigerant vapor from therefrigerating process enters the impeller chamber 15 from conduit 131.The refrigerant is compressed and exhausts through outlet 19 intoconduit 132 to cooler 134, where its temperature is reduced. Conduit 135carries the cooled liquid refrigerant to the refrigerating process area.Conduit 138 taps a portion of the cooled refrigerant, and connects intothe heat exchange section 13, from which the vaporized refrigerant thenpasses through conduit 140 to conduit 131 and then into the impellerchamber, where it is recompressed.

As stated above, the refrigerant material need not be of the compressedvapor type and may be of a material such as brine or other liquid.However, for the most efiicient cooling, high latent heat vaporizablematerials, such as the Freons, are preferred.

When pumping such materials as the Freons at their vapor pressure, it isimportant to prevent any boiling of the material in the impellerchamber. Accordingly, if the motor must be operated at a temperaturevery much high heat capacity refrigerant.

above the temperature of the Freon, such that a different lubricatingfluid must be used in the motor, it would be necessary to include athermal barrier, or insulating layer, in the end plate 36 to preventexcessive heat exchange across the end plate 36, which may cause boilingof the Freon in the impeller chamber. This would result in cavitation inthe pump and uneven pumping.

What is claimed is: t

1. A motor pump for the pumping of compressed vapor refrigerants,comprising a housing defining an impeller chamber, a motor chamber and aheat exchanger; an impeller in the impeller chamber, and a motor in themotor chamber; an inlet and an outlet in the impeller chamber forcirculation of fluid to be pumped therethrough, and an inlet and outletin the motor chamber for circulation of pumped fluid therethrough forlubricating'and cooling; a pressure relief connection between a highpressure portion of the impeller chamber and the motor chamber torelieve any increase in fluid volume in the motor chamber due to heatfrom the motor; a heat exchanging separator member in the heat exchangerseparating the heat exchanger into two compartments, one compartmentbeing in fluid flow connection with the inlet and outlet of the motorchamber so as to form a fluid flow circuit with the motor chamber, andthe other compartment of the heat exchanger being in fluid flowconnection with a high pressure portion of the impeller chamher, forheat exchange between pumped fluid passing through the impeller chamberand pumped fluid circulating in the motor chamber.

2. The motor pump of claim 1 wherein the heat exchanger comprises anouter housing defining a shell space having an inlet and an outlet, anda tube disposed within the shell space and having an inlet and anoutlet, the inlets and outlets of both tube and shell being attached ina manner separating the fluids passed therethrough for heat exchange.

3. The motor pump of claim 1 comprising a vent valve between the firstand second sides of the heat exchanger.

4. The motor pump of claim 2 wherein the tube defines the first side ofthe heat exchanger and comprises in addition a pressure-reducing flowrestriction placed in the inlet to the second side, whereby a pumpedrefrigerant liquid at its boiling point will flash immediately uponentering the second side.

5. A closed circuit compressed vapor type of refrigerating systemcomprising, in combination, in a closed fluid circuit interconnected byfluid lines, a refrigerant reservoir for a compressed vapor refrigerantheld therein partially in a lower liquid phase and partially in an uppervapor phase, an element to be refrigerated by refrigerant fluidcirculated in the circuit, and a canned motor pump for pumpingrefrigerant fluid in the circuit, the pump comprising a housing definingan impeller chamber and a motor chamber; an impeller in the impellerchamber, and a motor in the motor chamber; pressure ports between themotor chamber and a high pressure portion of the impeller chamber; aninlet and an outlet in the impeller chamber for circulation ofrefrigerant fluid to be pumped therethrough, and an inlet and an outletin the motor chamber for circulation of refrigerant liquid therethroughfor lubrication and cooling; a heat exchanger having a heat exchangingsurface separating the heat exchanger into two sides; fluid connectionsconnecting one side thereof with the inlet and outlet in the motorchamber, and second fluid connections connecting the other side thereofwith the impeller chamber and with the closed fluid circuit for heatexchange between refrigerant liquid circulating in the motor chamber andrefrigerant fluid passing through the impeller chamber and the fluidcircuit.

6. The refrigerating system of claim 5 wherein the heat exchangerincludes an outer shell defining a shell space having an inlet and anoutlet and a tube disposed within the shell having an inlet and anoutlet, the inlets and outlets of both tube and shell being connected tothe fluid connections in a manner separating the fluids passedtherethrough for heat exchange.

7. The refrigerating system of claim 6 wherein the tube defines thefirst side of the heat exchanger and the outlet from the shell side ofthe exchanger is in fluid flow connection with the upper portion of thereservoir.

8. The refrigerating system of claim 5 comprising a vent valve betweenthe two sides of the heat exchanger.

9. A compressed vapor type of refrigeration system comprising a closedfluid circuit interconnected by fluid lines, a compressor comprising ahousing defining a compressor chamber and a motor chamber, a compressorin the compressor chamber, a motor in the motor chamber, an inlet and anoutlet in the compressor chamber for circulation of fluid to becompressed therein, and an inlet and an outlet in the motor chamber forcirculation of refrigerant liquid therethrough for lubricating andcooling, pressure ports connecting the motor chamber to a high pressureportion of the compressor chamber; a heat exchanger having a heatexchanging surface separating the heat exchanger into two sides, oneside thereof being in fluid connection with the inlet and the outlet ofthe motor chamber, and the other side thereof being in fluid flowconnection with the compressor chamber for heat exchange betweenrefrigerant liquid circulating in the motor chamber with refrigerantfluid passing through the compressor chamber and the refrigerationsystem circuit; means for cooling the eflluent from the compressor, andan element to be refrigerated by refrigerant fluid circulated in thecircuit.

References Cited by the Examiner UNITED STATES PATENTS 1,968,566 7/1934-Moran 10387 2,510,632 6/1950 Hemphill 103-87 2,556,435 6/1951 Moehrl103-87 3,163,790 12/1964 White 31087 X MEYER PERLIN, Primary Examiner.

1. A MOTOR PUMP FOR THE PUMPING OF COMPRESSED VAPOR REFRIGERANTS,COMPRISING A HOUSING DEFINING AN IMPELLER CHAMBER, A MOTOR CHAMBER AND AHEAT EXCHANGER; AN IMPELLER IN THE IMPELLER CHAMBER, AND A MOTOR IN THEMOTOR CHAMBER; AN INLET AND AN OUTLET IN THE IMPELLER CHAMBER FORCIRCULATION OF FLUID TO BE PUMPED THERETHROUGH, AND AN INLET AND OUTLETIN THE MOTOR CHAMBER FOR CIRCULATION OF PUMPED FLUID THERETHROUGH FORLUBRICATING AND COOLING; A PRESSURE RELIEF CONNECTION BETWEEN A HIGHPRESSURE PORTION OF THE IMPELLER CHAMBER AND THE MOTOR CHAMBER TORELIEVE ANY INCREASE IN FLUID VOLUME IN THE MOTOR CHAMBER DUE TO HEATFROM THE MOTOR; A HEAT EXCHANGING SEPARATOR MEMBER IN THE HEAT EXCHANGERSEPARATING THE HEAT EXCHANGER INTO TWO COMPARTMENTS, ONE COMPARTMENTBEING IN FLUID FLOW CONNECTION WITH THE INLET AND OUTLET OF THE MOTORCHAMBERSO AS TO FORM A FLUID